The present invention relates to a laser welding apparatus for welding by use of a laser beam.
Remote laser welding has become common, in remote laser welding an object to be processes such as a workpiece is welded by remotely controlling a robot to which a laser emitting means, such as a scanner device or a laser machining head, for example, is attached. In such laser welding, a workpiece is welded by being irradiated with a laser beam from a position distant from the workpiece. Furthermore, the welding is performed on desired portions of the workpiece by remote control to move an arm of a robot or to rotate a reflecting mirror or the like provided to the laser emitting means so that different parts of the workpiece are irradiated with the laser beam.
When a workpiece made of a metal is irradiated with a laser beam for the purpose of welding, the metal vaporizes to produce a metal vapor (plume), and then the metal vapor blocks the laser beam. This results in impairment of the stability of the amount of heat applied from the laser beam to the workpiece, and results in deterioration of the welding quality. To address this, a method for welding has been heretofore adopted, in which a fan is installed at a position, for example, a position which is located distant from and at a side of a workpiece, the fan blows air (gas) on the workpiece, and therefore the metal vapor (plume) is blown away by the air.
In addition, U.S. Publication Application No. 2007/0210040 A1 discloses a laser welding apparatus having a configuration in which fumes are blown away by air ejected from an air spray nozzle, and the air spray nozzle is attached to a laser machining head attached to a tip of a robotic arm. In this laser welding apparatus, the air spray nozzle is disposed at a side of the workpiece or at a side of the laser beam, and the air is ejected in such a manner as to cross the laser beam.